In the rotary tablet presses used in the prior art, the product which is to be compressed, such as, in particular, a powder for the production of medicaments or a powder for the production of cleaning tablets or the like, is fed, via suitable channels or hoses, a hopper and a feed member, referred to as a filling shoe, to the dies which are interchangeably inserted in the die plate, with the fed-in powder being pressed with the holes of said dies to form a tablet of the desired shape by means of punches moved in opposite directions. The hopper and the channels can also form an integral component of the filling shoe. Here, the filling shoe can be mounted in a fixed position relative to the die plate or else be fastened to a pivoting device which in the course of operation is pivoted into its operating position in which the filling shoe assumes a predetermined position relative to the dies in the die plate. Impeller wheels or other movable distribution members which are motor-driven are frequently arranged inside the filling shoe so that the product or powder which is to be compressed can be better distributed over the die holes which are to be filled by means of the filling shoe. The filling shoe should at the same time ensure that the product to be compressed, such as, in particular, powder, substantially only fills the die hole to the desired filling height in order to avoid product losses and to achieve a favorable metering accuracy of the product or powder to be compressed. For this purpose, a seal which is made of a material which is optimally tailored to the product to be compressed is fastened to the underside of a bottom wall of the filling shoe housing that surrounds the discharge opening. Customary materials for such seals can be, for example, bronze, stainless steel or plastic and, depending on the product to be compressed that is used, the intended purpose, the wear resistance of the seal, etc., the seal must be exchanged for a new seal or else for a seal made of another material when the product to be tableted is changed.
The process of changing or exchanging the seals in the prior art involves loosening a large number of screws which engage through the bottom wall of the filling shoe housing and pass into associated threaded holes in the seal. It is also known practice to insert seals made of bronze, for example, into suitable dovetail guides or the like by means of a rib and to anchor them therein in a positively locking manner. The more abrasive the product to be compressed and the smaller the free gap is set between the seal and the surface of the die plate, the quicker the seal wears and a change of seal on the filling shoe must take place, which change requires relatively long downtimes of the tablet press. Since powder dust which is to be briquetted, for example, clogs the threaded holes or undercut guides, even changing the seal can present problems and cause relatively long downtimes.